稀土和钍的纸上反相层析分离

Separation of Rare Earths and Thorium in TBP + PMBP + HCl or TBP + PMBP + Kerosene + HCl Synergistic System by Reversed Phases Paper Chromatography

本文研究了TBP-PMBP-HCl体系和TBP-PMBP-煤油-HCl体系在低酸度条件下,以纸上反相层析法模拟液液萃取分离钍及稀土的可能性.在规定的实验条件范围内,[H^+]≥O.5M时,获得钍与稀土分离的良好效果.[H^+]=O.2-0.4M时,也能使若干单一稀土分离,并用斜率法探讨了稀土在此协萃体系中所形成的络合物的组成.

Papers treated with benzene solution of TBP+PMBP or with kerosene solution of them are used for chromatography. The amounts of TBP and PMBP in various proportion involved in the solutions are listed in following table:??When benzene volatilizes, TBP + PMBP (system I) or TBP + PMBP + kerosene (system II) is held stationary on the paper, and diluted hydrochloric acid aots as mobile phase for development. The test solutions applied to paper are solutions of chlorides of La^(3+), Ce^(3+), Gd^(3+), Y^(3+), Yb^(3+) and Th^(4+).Under the assigned experimental conditions and refer to the R_f values of various metal ions, when [H^+] ≥ 0.5M, we get a satisfactory separation of Th from rare earths (R_(f (Th)) →0; R_(f (R·E))→0.85～1.0). For rare earths, as [H^+] =0.2～O.4 M, they may be also separated each other with only the exception of Y and Yb in system (I).The reaction of complexes forming is assumed in common:M_((aq)) + nT_((o)) + mHA_((o)) ?MT_nA_(m(o))+mH^+_((aq))where, T and HA represent TBP and PMBP respectively. As we connect the distribution coefficient D of metal ion between two phases to its corresponding R^f value by Martin's equation, then we derive it as:R_M = nlg[T] + mlg[HA] + mpH + constantDiagrams of R_M against lg[TBP] and lg[PMBP] are plotted respectively. From their slopes, values of n and m could be calculated, and show that under the experimental conditions the composition of complexes may be RE (PMBP)_2TBPCl and RE(PMBP)TBPCl_2 for La^(3+), Ce^(3+) and Gd^(3+); Y^(3+) forms Y(PMBP)_2TBPCl; and Yb^(3+) as the form of Yb(PMBP)_2TBPCl and Yb(PMBP)_2Cl.